Serena and Venus Williams have commited to the U.S. Tennis Association that they will play the Fed Cup final against Italy in November.
Neither Williams has competed in the Fed Cup since 2007.
"You always want to have your best players," U.S. captain Mary Joe Fernandez said on Thursday. "I am very excited that Venus and Serena have made themselves available."
The United States lost to Italy in last year's Fed Cup final, and they hasn't won the title since 2000.
The best-of-five tie is from Nov. 6 to 7 on an indoor hard-court at the San Diego Sports Arena.
Also on the U.S. team are Melanie Oudin, Bethanie Mattek-Sands and Liezel Huber. Fernandez called it "one of the strongest lineups in years."